Finding the Fourth Proportional to 1,375.86, 1,898.70 and 786.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,375.86 : 1,898.70 = 786.60 : x
2. Step 2: Convert to fraction form
   1,375.86/1,898.70 = 786.60/x
3. Step 3: Cross multiply
   1,375.86x = 1,898.70 × 786.60
4. Step 4: Simplify right side
   1,375.86x = 1,493,517.42
5. Step 5: Solve for x
   x = 1,493,517.42/1,375.86
6. Step 6: Final answer
   x = 1,085.52